1. Field of the Invention
The present invention relates to a rotary window cleaner for a vehicle and a rolling stock of other kinds, rail car, a vessel, an airplane and the like.
2. Description of Prior Art
The conventional rotary window cleaner of this kind is shown in the U.S. Pat. No. 5,210,900, and comprises two wipers disposed proximate with respect to each other on the front window pane, driving motors separately provided respectively for said two wipers, and a limit switch for actuating other of two driving motors after one of two driving motors is actuated, in order to rotate the two wipers to the opposite direction with a lag angle formed between two wipers for wiping out the rain drops dropped on the front window pane. This publicly-known rotary window cleaner is provided, in order to avoid the possible interference between the two wipers which would be caused by elimination of the lag angle there-between when the two motors are reached to certain rotational speed, with a coupling mechanism to connect the rotating shafts of said two driving motors to each other which comprises a screw portion formed at the end of the rotating shaft of one motor, a drum portion having a groove formed at the opposite end of the rotating shaft of other motor, and a planetary element slidable along the groove formed on said drum portion and threadedly engagable with the screw portion. Thus, the two wipers are rotated in a condition holding the lag angle there-between by actuating two motors with a common driving source after a certain period of time of the other driving motor actuated.
The conventional rotary window cleaner as described above has such disadvantages that the planetary element for coupling and decoupling the rotating shafts of the driving motors cannot be easily released from the coupling and decoupling positions of the two rotating shafts because the planetary element is screwed strongly into the opposite ends of the screw portion of the rotating shaft, thereby not making coupling and decoupling said two rotating shafts more accurately, and that on the other hand, the planetary element would be easily be damaged by the groove of the drum portion provided on the rotating shaft of the other driving motor.